Rotary device



April 2 4, 1962 P. w. s. PERssoN ROTARY DEVICE Original Filed` Feb, 5, 1959 INVENTOR. PER WALTHER SGVARD PERSSON vnited `States The present invention relates to a rotor device and more particularly to a device having male and female rotors with cooperating lands and grooves wherein the casing supporting the rotors is provided with a single end plate and the rotors are supported by this single end plate in a novel manner to minimize vibration. This application is a continuation application based on my prior U.S. application Serial No. 791,381 filed February 5, 1959, now abandoned.

Heret-ofore rotary devices wherein the rotors 'are supported in a casing by a single end plate are known. Devices of this type are shown, for example, in prior Patents 2,847,l57 and 2,868,442. Rotary devices of this type have been used with considerable success at lower speeds. However, at high speeds it has been found that the free ends of the rotors have been subject to severe oscillation and vibration. This has resulted in seizing of the rotors in the casing or in metal fatigue in the spindle causing fracture thereof.

According to the present invention the foregoing `disadvantages of prior art devices of this type are avoided by mounting the rotors in the single end plate so as to provide considerably increased bearing and supporting surfaces and by supporting the rotors so that damage to the spindle by execssive strain is avoided. This is accomplished by journalling the sleeves supporting the rotors in the end plate `of `the casing so that the 4bearings are disposed between the outer surface of the sleeve and the casing. In addition means is provided for reinforcing the spindle adjacent the end plate in order to minimize vibration and fatigue of `that element.

An object of the present invention is to provide a mounting for the male and female rotors of a rotary device whereby vibration is substantially eliminated at high running speeds.

Another object of the present invention is to provide a mounting for a rotary device wherein a single end plate is provided and the sleeve supporting the rotors is journalled within a recess in the end plate so as to give increased lbearing support for the rotors.

Other objects and many of the attendant advantages of the present invention will become apparent upon consideration of the following detailed specification in connection with the accompanying drawing wherein:

FiG. 1 is a vertical longitudinal section through a rotary device constructed in accordance with the present invention along the line 1-1 of FIG. 2,

FIG. 2 shows an end view of the rotary device in a direction indicated 'by the line 2 2 of FIG. 1 and,

FIG. 3 is a horizontal longitudinal section through the device along the line 3-3 of FIG. 2.

There is provided a casing including an integral jacket portion 12 and end plate portion 14. The jacket portion is provided with a plurality of outwardly extending tins 16 for cooling. The jacket has a pair of bores 1S and 20 (FIG. 2) which intersect each other along the lines 22 and 24 and provide lbores for a male rotor 28 and a female rotor 32. The male rotor is provided with convex lands 26 and the female rotor has six concave lands 30.

The male and female rotors 2S and 32 comprise sleeves 34 and 36 respectively and these sleeves are rotatably l aient 3,03Ll30 Patented Apr. 24, 1962 'ice journalled in the casing structure in a manner to be described more fully hereinafter. The sleeve 34 is secured to a central shaft 76 by means of cap 70 and bolts 64. The bolts 64 extend through the sleeve, securing the sleeve to the male rotor 28. It can `be seen that by virtue of this construction rotation of the shaft 76 will rotate the end cap 70, sleeve 34 and the male rotor part.

The sleeve 36 is secured -to the female rotor part 32 by means of bolts 74 which also secure the end cap 72 in place over the end of the sleeve.

There is provided a bore 44 in the end plate and this lbore receives a spindle 38 which is secured in place by means of locking nut 48. lt will be noted that the end plate is provided with an enlarged portion or boss 46 to provide reinforcement for the spindle mounting. The spindle 4G disposed within the female rotor is similarly mounted and secured in place on the end plate.

The spindles are tapered as shown to a maximum dimension adjacent the mounting in the end plate 14. The

`outer end of the spindle provides a bearing for the outer end of the sleeves 34 and 36 and these bearings may comprise, for example, ball Ibearings 52. At the inner ends the rotor sleeves 34 and 36 are journalled within recesses in the end plates by, for example, roller 'bearings 54. In orderto prevent the lsleeves 34 and 36 from sliding, locking nuts 58 are threaded on the ends 60 of the spindle so as to abut the ball bearings S2. Sealing rings -63 are mounted outside the roller bearings `54 and serve as sealing means between the sleeves 34 and 36 and the end plate 14.

Means for transmitting power may be mounted on the driving shaft 76 of the male rotor. This means may comprise a pulley 98 carried by bearings 100 and 102 which pulley is threaded on the end 104 of the spindle 36. A cap 106 secures the bearings 100 and 102 as well as a spacer ring 108 disposed therebetween. An abutment 110 is disposed on the inner end of the pulley 9S and this abutment rests against ball bearing 102 and at the outer end the pulley 98 is secured to the cover 106 by means of 'balls 112. Guide pin 114 secures the cap 106 to the shaft 76. Thus, lby virtue of this construction, rotation of the pulley will rotate the shaft 76 and the male rotor.

It can be seen that according to the present invention the female rotor is driven solely by engagement with the male lands in the female grooves. Thus, synchronizing gears between the male and female rotors may be dispensed with. This has been accomplished without any risk of seizing between the male `and female rotors because of the precise centering and parallel mounting of the rotors.

It is possible to further prevent seizing of the rotors by making the sleeves of the rotors of different materials. The sleeve 34 of the male rotor may consist of a pressed fibrous material bound with a suitable agent as, for example, asbestos pressed with suitable plastic such as silicon plastic while the sleeves 36 of the female rotor may consist of steel or similar material.

In the illustrated embodiment of the rotary device as a low pressure compressor the casing provides a radiallyaxially extending outlet 80. The inlet of the device comprises -the open end 82 of the jacket 14 and in `order to prevent a direct communication between the inlet and outlet openings a covering plate 84 is fastened by means of bolts 36 at the open end of the jacket, thus covering the jacket opening so as to prevent communication between the inlet and outlet openings. The inlet 82 is thus 'bordered by the inner contours of the 'bores 18, 20 of the rotors and the border profiles 88, and 92 of the covering plate.

Lubrication of the bearing means for the sleeves of the male and female rotor may be by means of grease through the utilization of grease cups 94 and grease channels 96 as shown in FG. 3 and by means of oil in which case supply openings 12) and plugs 122 such as shown in FIG. 1 are provided.

It can be seen that according to the present invention the rotors are mounted on sleeves which are journalled at the free ends on tapered spindles and at the inner ends are journalled within recesses in the end plate. Maximum bearing surface and support is provided for the end of the sleeve adjacent the end plate. By reinforcing the spindles in the manner shown vibration of the apparatus is considerably reduced and the risk of fracturing the spindle is minimized.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. What is claimed as new and desired to be secured by Letters Patent is:

1. A rotary device for changing the pressure of a medium, comprising a male rotor and at least a female rotor having cooperating helical lands and grooves, a casing having a circumferential jacket portion enclosing the rotors and a single end plate supporting and holding the rotors against axial displacement, spindle members mounted on said end plate in recessed portions thereof and projecting into said casing, said rotors each including a sleeve member encircling a spindle member and having one end thereof protruding into a corresponding recessed portion of said end plate and journalled by bearing means externally located in relation to said sleeve member in said recessed portion, the other end of said sleeve being journalled by bearing means internally located in relation to said sleeve member on the remote end of the spindle.

2. A rotary device as claimed in claim 1, in which each said spindle is Widening in the direction toward said end plate whereby the end of said spindle is reinforced in the direction toward the end plate.

3. A rotary device for changing the pressure of a medium, comprising a male rotor and at least a female r0- tor having cooperating helical lands and grooves, a casing having a circumferential jacket portion enclosing the rotors and a single end plate supporting and holding the rotors against axial displacement, said rotors each including a sleeve member and a spindle member carrying the corresponding sleeve member, one end of each of said spindle members inserted into a bore formed into the end plate, each said spindle widening conically in the direction toward said end plate to provide means therein for a bearing ush with the rotor sleeve whereby the ends of said rotors adjacent the end plate end thereof are reinforced -by larger spindles.

References Cited in the tile of this patent UNITED STATES PATENTS 1,083,329 Lancia lan. 6, 1914 1,418,741 Stallman .lune 6, 1922 2,279,136 Funk Apr. 7, 1942 2,407,753 W'allgren Sept. 15, 1946 2,633,807 Collura Apr. 7, 1953 2,635,552 Dale, et al. Apr. 21, 1953 2,642,808 Thomas June 23, 1953 2,847,157 Nilsson Aug. 12, 1958 2,868,442 Nilsson Jan. 13, 1959 FOREIGN PATENTS 437,042 Great Britain Oct. 23, 1935 

